INSTRUCTIONS
Date: 23rd March 2015
ARRI Camera
Sensor Cover Glass Cleaning
Version History
Version
Author
Change Note
2014-09-11
Poetsch
Initial version
2015-03-23
Poetsch
Minor text corrections
Table of Contents
Version History .................................................................................................................. 2
Table of Contents ............................................................................................................... 2
Introduction ........................................................................................................................ 3
1 Inspecting for dust/dirt ................................................................................................... 3
2 Cleaning ........................................................................................................................... 4
2.1 Contact-free cleaning .......................................................................................... 4
2.2 Dry cleaning ......................................................................................................... 5
2.3 Wet cleaning ........................................................................................................ 6
3 General precautions ....................................................................................................... 7
Contact ................................................................................................................................ 7
Sensor Cover Glass Cleaning – Instructions Page 2 of 7
Introduction
During normal use, changing the lens of a camera allows dust or dirt to enter the lens bay. Some of these
particles may settle on the protective sensor cover glass, resulting in image artifacts. Regular inspection and
cleaning of the sensor cover glass reduces the risk of these artifacts showing up.
Cleaning is always performed on the protective cover glass, which is the top sheet of the optical filter array
located in front of the sensor. The sensor itself is sealed to protect it from environmental influences.
Perform all cleaning in a protected environment, to avoid additional contamination during the cleaning
process.
The following instructions are the ARRI recommended techniques, which are applied in our service centers
and have proven to be effective.
Any cleaning is performed at your own risk. ARRI takes no responsibility for damages caused by improper
cleaning.
1 Inspecting for dust/dirt
By inspecting the sensor cover glass for dust and dirt, one can easily determine whether cleaning is
necessary.
Required materials:
- Camera lens
- HD Monitor
- Uniform white image target area
Instructions:
1. Attach the lens to the camera.
2. Set the lens focus to infinity.
3. Set the lens aperture to F16 or above.
(Note: Dust specs are less visible at wider apertures.)
4. Connect the HD monitor to the camera image output.
5. Aim the camera at the image target.
6. Adjust the exposure of the image through camera FPS, Shutter Angle/Exposure Time or Exposure
Index. Variation of exposure level may be required. Signal clipping must be avoided.
7. Inspect the image of the HD monitor for dust and dirt.
Dust/dirt particles appear as local changes in image brightness. If particles are visible, cleaning is
recommended.
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2 Cleaning
2.1 Contact-free cleaning
Start by blowing dirt off the sensor cover glass with a bulb blower. Two types of buld blowers are available,
- Bulb blowers without integrated filter:
- Bulb blowers with integrated filter:
Never touch the sensor cover glass.
Never use blowers with compressed air or gas. The flowing air might cool down the cover glass until it
cracks. Bottled air also contains propellants that may deposit on the cover glass.
Never use air blowers with high pressure. They might damage optical surfaces.
Never use air dust-guns.
Never use blow-brushes. The brushes catch dust and distribute it instead of removing it.
Sensor Cover Glass Cleaning – Instructions Page 4 of 7
2.2 Dry cleaning
Dry cleaning has a number of benefits over wet cleaning (described in the next step), in that it is residue-free
and generates few particles itself while showing a good dust/dirt absorption.
Product examples are:
- DUST-Aid Platinum:
(http://dust-aid.com/)
- Texwipe Absorbond Swab TX762 with Long Handle:
(www.texwipe.com
)
Instructions:
1. Always store swabs inside original bag. Remove one by one for use. Store swab bag in a dust-
protected environment.
2. Use swab with gentle touch. Never apply pressure.
3. Swab the sensor cover glass horizontally in 3 or more steps. Do not touch the border.
Sensor Cover Glass Cleaning – Instructions Page 5 of 7
4. Swab around the border.
Note: The swab around the border should alwas be the final step to avoid smearing of material from
the border to the surface of the glass.
Never use one swab twice.
Never touch the cleaning area of the swab.
Never scratch the surface. Make sure no grain or other particle is between the swab and the sensor
cover glass.
2.3 Wet cleaning
Wet cleaning is recommended to remove grease or sticky dirt that cannot be removed by contact-free or dry
cleaning.
Any cleaning liquid leaves residues. Choose a liquid that leaves as little residue as possible.
Liquids should be judged for their:
- High purity: Particles <5 mg/liter (so called “pa” liquids = pro analytica)
- High volatility
Recommended liquids with a high purity and volatility are:
- Petroleum ether, also known as Benzene
- Isopropyl alcohol, also known as Isopropanol
- Ethyl alcohol, also known as Ethanol
- or any mixture of these. An example for a popular mixture is 85% Petroleum ether and 15%
Isopropyl alcohol.
Never use Acetone. It can solve paint from the sensor border and spread it over the sensor cover glass.
Note: Some liquids like Petroleum ether and Isopropyl alcohol are forbidden on flights. Pay attention to
safety instructions and flight regulations when boarding a plane.
Instructions:
1. Use “Texwipe Absorbond Swab TX762 with Long Handle” (see above).
2. Always store swabs inside original bag. Remove one by one for use. Store swab bag in a dust-
protected environment.
3. Pour cleaning liquid into separate container. Never apply liquid to swab directly from storage
container.
4. Apply cleaning liquid to swab.
5. Use swab with gentle touch. Never apply pressure.
Sensor Cover Glass Cleaning – Instructions Page 6 of 7
6. Swab the sensor cover glass horizontally in 3 or more steps. Do not touch the border.
7. Swab around the border.
Note: The swab around the border should alwas be the final step to avoid smearing of material from
the border to the surface of the glass.
Never use one swab twice.
Never touch the cleaning area of the swab.
Never scratch the surface. Make sure no grain or other particle is between the swab and the cover
glass.
3 General precautions
Always place a lens or a lens mount protective cap on a lens mount to prevent dirt or dust from entering the
camera.
Read the camera user manual for additional information.
Contact
In case you have questions or recommendations, please contact the ARRI Camera Service
via phone: +49 (0)89 3809-2121
or email: service@arri.de
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